They specifically lowered the price when buying without Apple payment processing.
When preparing for a battle like this that's basic optics. Get the users on your side. But don't be fooled for a minute, in the end this is simply Epic not liking to give Apple a cut of what they consider their income. What surprises me is how easily people are fooled about this.
That's not true at all. This whole thing started when Epic released a direct pay feature in their iOS app that gave a 30% discount for direct pay straight to the users. You can argue whatever you like about the big corps legal departments, but it's inarguable that users using the direct pay feature are paying less right now.
So can they just make anything bought through iOS cost 30% more, but people can buy it from the website (not through iOS) without the Apple markup? I'd think people would quickly learn to buy from the lower cost option.
I think Apple requires IAP be the same price as anywhere else.
That 30% is a cost to Epic and that cost has to be paid by someone.
Just like any other cost, more often than not these costs are just passed on to the customer.